The present invention relates to heating units, and more particularly pertains to wood burning heating units such as stoves and fireplaces. In conventional stoves and fireplaces, a large portion of the heat from the fire, along with many partially and completely unburned gasses are exhausted through the chimney. In addition to creating air pollution problems, the exhaust of unburned combustion gasses results in reduced heating efficiency. Accordingly, the present invention is directed to the provision of an improved wood burning heating unit possessing combustion air and exhaust gas flow paths adapted to maximize heating efficiency and minimize the exhaust of unburned gasses.